diff --git a/ChangeLog b/ChangeLog
index fe7cf2486..2122abb10 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -43,6 +43,7 @@
  + Improved text wrapping of UTF8 text.
  + When duplicating a parent recurring task, a new recurring parent task is
    created.  When a child recurring task is duplicated, a plain task is created.
+ + The 'diagnostics' command now checks for duplicate UUID values in the data.
 
 # Tracked Features, sorted by ID.
  + Added feature #52, which provides improved text-wrapping support for UTF-8
diff --git a/src/commands/CmdDiagnostics.cpp b/src/commands/CmdDiagnostics.cpp
index a7fd6feb5..b95824206 100644
--- a/src/commands/CmdDiagnostics.cpp
+++ b/src/commands/CmdDiagnostics.cpp
@@ -309,6 +309,37 @@ int CmdDiagnostics::execute (std::string& output)
         << "x"
         << context.getHeight ()
         << ")\n";
+
+    // Scan tasks for duplicate UUIDs.
+    std::vector <Task> all = context.tdb2.all_tasks ();
+    std::map <std::string, int> seen;
+    std::vector <std::string> dups;
+    std::string uuid;
+    std::vector <Task>::iterator i;
+    for (i = all.begin (); i != all.end (); ++i)
+    {
+      uuid = i->get ("uuid");
+      if (seen.find (uuid) != seen.end ())
+        dups.push_back (uuid);
+      else
+         seen[uuid] = 0;
+    }
+
+    out << "      Dups: "
+        << format (STRING_CMD_DIAG_UUID_SCAN, all.size ())
+        << "\n";
+
+    if (dups.size ())
+    {
+      std::vector <std::string>::iterator d;
+      for (d = dups.begin (); d != dups.end (); ++d)
+        out << "            " << format (STRING_CMD_DIAG_UUID_DUP, *d) << "\n";
+    }
+    else
+    {
+      out << "            " << STRING_CMD_DIAG_UUID_NO_DUP
+          << "\n";
+    }
   }
 
   out << "\n";
diff --git a/src/en-US.h b/src/en-US.h
index 7193d6a7a..31f89e2d0 100644
--- a/src/en-US.h
+++ b/src/en-US.h
@@ -407,6 +407,9 @@
 #define STRING_CMD_DIAG_TESTS        "Tests"
 #define STRING_CMD_DIAG_UUID_GOOD    "1000 unique UUIDs generated."
 #define STRING_CMD_DIAG_UUID_BAD     "Failed - duplicate UUID at iteration {1}"
+#define STRING_CMD_DIAG_UUID_SCAN    "Scanned {1} tasks for duplicate UUIDs:"
+#define STRING_CMD_DIAG_UUID_DUP     "Found duplicate {1}"
+#define STRING_CMD_DIAG_UUID_NO_DUP  "No duplicates found"
 #define STRING_CMD_DIAG_NONE         "-none-"
 #define STRING_CMD_PUSH_USAGE        "Pushes the local files to the URL"
 #define STRING_CMD_PUSH_SAME         "Cannot push files when the source and destination are the same."